ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
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<cr1901_modern>
I managed to build Far Stocks. The resultant ROM does not run in an emulator and it isn't _quite_ identical to a release ROM. But it's close.
<cr1901_modern>
(Oh, and then my laptop bluescreened and completely trashed my atom configuration)
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<andlabs>
Far Stocks?
<andlabs>
wait oh
<andlabs>
the second message is not related ot the first message
<andlabs>
in that case, what's an atom configuration?
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<andlabs>
oh atom the text editor?
<TD-Linux>
ok I finally got the chips
<TD-Linux>
if you're really bored you can watch me struggle in real time with basic electrical engineering twitch.tv/tdlinux/
<TD-Linux>
whitequark, is there a reset for the shift registers?
<TD-Linux>
whitequark, is there a way to set the size of the eeprom independently from the numger of address lines on the shifters?
<TD-Linux>
ah nvm not necessary nvm
<TD-Linux>
odd behavior I'm seeing on this eprom with health check is that the combination of the first two passes show all the eprom words as unstable, but the rest of the passes are ok
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<TD-Linux>
figured out a few things. my eprom is not actually corrupt, I used the wrong chip variant for the tl866ii which was apparently too fast for this super slow chip (?)
<TD-Linux>
with the shift registers, my glasgow dump is incorrect above 0x200. I can't figure out why, A9 into my eprom looks correct.
<TD-Linux>
ohhh! fixed. I thought 512 was suspiciously similar to max usb packet size, so I tried reflashing glasgow firmware, and that fixed it. I guess I must have had really old firmware on it and never thought of reflashing it
<TD-Linux>
ok my health checks are passing. I just need to pick up the damaged eproms now (that I don't have a damaged one)
<TD-Linux>
btw a uva laser pointer does nothing to this eprom (in a reasonable timeframe)
<TD-Linux>
ok I wrote a chip at 18V (rather than 21V) and it indeed failed to read back. and I ran sweep and was able to recover it at 4.65V!
<TD-Linux>
ok not quite. it reads "stably" about at that voltage and it finds it every time. however the data is not correct. but also I think my "programming at 18V" trick is, at best, not very realistic
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<cr1901_modern>
andlabs: Far Stocks... it's a game about where you want to invest in the stock market, but they're too far away :)
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<andlabs>
yes
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<cr1901_modern>
TD-Linux: Really cool you were able to save that EPROM via experiment :)
<TD-Linux>
not exactly
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<ZrX-oMs>
In light of recent events, Nintendo could use a good plumber.
<cr1901_modern>
I wrote a diff program to compare one of the nearly-final protos to the actual final ROM. Unfortunately, there are enough diffs that myers' algorithm explodes in complexity.
<ZrX-oMs>
Something that also detects if differing offsets have identical content?
<cr1901_modern>
AFAIU, myers' algorithm accounts for that when it finds the longest common subsequence
<whitequark>
TD-Linux: yeah i should add an option to set eprom size
<whitequark>
it doesn't necessarily hurt to do it the way it's done
<whitequark>
but it's not very friendly
<whitequark>
TD-Linux: no reset, seemed superfluous
<whitequark>
TD-Linux: i'm curious what the wrongness is
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<andlabs>
ah good telegram jsut broke
<andlabs>
no it fixed itself since I said that
<TD-Linux>
whitequark, you mean with my partially programmed eprom?
<whitequark>
yes
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<whitequark>
TD-Linux: a-ha
<whitequark>
so i actually observed that with my eprom, possibly
<whitequark>
that if i lower voltage low enough for it to become *stable*, it just always reads 0xff
<whitequark>
so i should reproduce it
<whitequark>
because i think the current command set is not sufficient
<TD-Linux>
ok I think the garbage at the end was actually introduced by my programmer somehow, as I don't see it on any of my other blank eeproms. bonus points if it's random memory from my pc
<whitequark>
lol how
<whitequark>
TD-Linux: how would you expect to configure write timings
<TD-Linux>
by picking my chip from a database
<whitequark>
yeah but there's no database
<whitequark>
what about then
<whitequark>
i'm not actually very interested in collecting a EPROM database and it's unlikely to happen in any meaningful way
<TD-Linux>
time to chip enable, and length of write pulse?
<whitequark>
hm
<whitequark>
the applet doesn't actually use chip enable
<whitequark>
it's just hardwired to active
<whitequark>
let me give more context
<whitequark>
the datasheet specifies a lot of timings but a bunch of them are just zero
<whitequark>
like address setup and data hold
<TD-Linux>
I think you have to use chip enable to write?
<whitequark>
and... it's not clear to me which ones are important
<whitequark>
hm
<whitequark>
i'm reading AT29C010A
<TD-Linux>
oh that's flash, that will be different
<whitequark>
agh
<TD-Linux>
that said, can probably swap WE for CE here and use the same timing values
<whitequark>
reading at27c128 docs
<whitequark>
doesn't seem to require CE operation for writins
<TD-Linux>
oh that one seems just to trigger it on VPP
<TD-Linux>
m2732a datasheet wants VPP first then E
<TD-Linux>
it might work the other way around, though
<whitequark>
i thought it triggers on PGM?
<whitequark>
it seems extremely weird to trigger on VPP, given that might have some serious latency
<whitequark>
also, why even have PGM then
<TD-Linux>
ah I missed PGM
<TD-Linux>
yeah so then PGM would be equivalent to E on the m2732a
<whitequark>
hmm
<TD-Linux>
for the purposes of writing (even though it also has a CE where m2732a has E)
<whitequark>
ohhhhhh i see
<whitequark>
it uses a comparator or something
<whitequark>
this is uh
<whitequark>
it's kind of obnoxious
<whitequark>
i don't actually know how to support it nicely
<whitequark>
*squints* wait
<whitequark>
"ST" stands for "SGS-THOMPSON"?!
<whitequark>
*THOMSON
<TD-Linux>
yup, though I think official corporate lore has dropped it